Method and means for treating fibrous materials and articles produced thereby

ABSTRACT

This invention relates to a method and means for achieving a degree of oil and/or water repellency by fibrous materials by exhausting on such materials as textiles and the like acidic nonionic emulsion system containing fluorocarbon polymer, then achieving the desired oil and/or water repellency with subsequent heat curing.

United States Patent METHOD AND MEANS FOR TREATING FIBROUS MATERIALS AND ARTICLES PRODUCED THEREBY 8 Claims, No Drawings U.S.Cl 117/121,

117/138.8A,117/139.5A,ll7/l4l,117/143 A, 117/161 UT, 117/161 UB Int. Cl ..D06m 15/00, B44d 1/06 Field of Search 1 17/121,

139.5 R, 161 UC, 138.8 A,139.50,141,135.5, 143 R; 260/296 F [56] References Cited UNITED STATES PATENTS 2,642,416 6/ l 953 Ahlbrecht et al. 260/835 2,718,478 9/1955 Fluck etal. 117/141 X 2,803,615 8/1957 Ahlbrecht et al. 260/296 2,826,564 3/1958 Bovey et al. 1. 260/835 2,839,513 6/1958 Ahlbrecht et al. 260/861 2,841,573 7/1958 Ahlbrechtetal. 117/141 X 2,953,526 9/1960 Bergman et al..... 117/1395 3,178,309 4/1965 Harding 117/1395 Primary Examiner-William D. Martin Assistant Examiner-Theodore G. Davis Attorneys-Norman Blumenkopf, Richard N. Miller, Murray M. Grill, Herbert S. Sylvester, Thomas J. Corum, Ronald S. Cornell and Robert L, Stone ABSTRACT: This invention relates to a method and means for achieving a degree of oil and/or water repellency by fibrous materials by exhausting on such materials as textiles and the like acidic nonionic emulsion system containing fluorocarbon polymer, then achieving the desired oil and/or water repellency with subsequent heat curing.

METHOD AND MEANS FOR TREATING FIBROUS MATERIALS AND ARTICLES PRODUCED THEREBY It is known that textile materials can be made water-resistant and oil-repellent by treating them with aqueous dispersions of organic compounds which contain a plurality of perfluoroalkyl radicals. In the past it has been necessary to employ quatemaries to ensure proper exhaustion of the fluorocarbon compound during the aqueous rinse cycle of a washing operation, for instance.

It has been discovered that nonionic emulsifiers can be used without the specific addition of quaternary compounds in rinse cycle exhaustion of cationic fluoropolymer emulsions and emulsion polymer extenders provided that the pH is adjusted to be acidic. While prior art quatemaries have been efficacious, they pose a problem on the fabric so treated as they affect the light fastness of dyes and in some instances cause discoloration. They also react with anionic detergents utilized in the laundry.

Accordingly, it is contemplated that the present invention relates to a method for developing oil and water repellency in fibrous materials such as textile materials comprising exhausting on such materials a fluorocarbon polymer in an aqueous emulsion system at a pH of between 3.0 to 5.5; then drying said treated materials, thereafter heat treating the materials to achieve the water and oil repellency benefits of the fluorocarbon polymer.

The fluorochemical compounds, which are used to impart water and oil repellent properties, can have chemical structures that vary widely. For example, acrylates and methacrylates of hydroxyl compounds containing a highly fluorinated residue and their polymers and copolymers can be used. Fluorochemical compounds of this type are defined with greater particularity in U.S. Pat. Nos. 2,642,416, 2,826,564, 2,829,513, and 2,803,615. Other fluorochemical compounds which can be employed as oil and water-repellent agents include the chromium coordination complexes of saturated perfluoromonocarboxylic acids of which the chromium complexes of perfluorobutyric acid and perfluorooctanoic acid are representative. Fluorochemical compounds suitable for the process of the invention are available commercially, many of which have been patented and assigned to the Minnesota Mining and Manufacturing Company which have the following formula:

Where X is an integer in the range of 13-13, R is methyl, ethyl, propyl, butyl, amyl, hexyl, R" is an alkylene radical having l-l2 carbon atoms and R' is hydrogen, methyl or ethyl. Another applicable fluorochemical compound are compounds manufactured by DuPont, such as polymers of 1,1,7- trihydroperfluoroheptyl acrylate; l, l ,7-trihydroperfluoroheptyl methacrylate; l,l-dihydroperfluoroctyl methacrylate and a terpolymer latex product consisting of 97.5 percent perfluoromethacrylate monomer, 2 percent butyl acrylate and 0.5 percent N-methylol acrylamide.

In order to adjust the pH to between 3.0-5.5, a number of acidic compounds are applicable, however, acetic acid is preferred. The acidic compound selected should not generally be of the type which has a tendency to decompose the other components of the system, that is, an oxidizing acid and the like.

A broad spectrum of nonionic emulsifiers are applicable to the present invention. For instance, lgepal CO 630 which is nonylphenoxyethyleneoxyethanol, has been found to be particularly useful. Other nonionic detergents applicable are the Pluronics (condensates of ethylene oxide with a hydrophobic base formed by condensing propylene oxide with propylene glycol), and RA 35 a polyethoxylated long chain linear alcohol as further described in U.S. Pat. Nos. 3,022,335, 3,036,l 18, 3,036,130, 3,101,374 and 3,203,955-said nonionic detergents are marketed by Wyandotte Chemicals Corporation; or the Hyonics (e.g., fatty alkylolamides-marketed by Nopco Chemical Co.). While not limited thereto the use of liquid nonionic detergents are most suitable for blending purposes.

Extenders can be used efficaciously in the formulation. For instance poly 2,3-dichlorobutadiene is applicable. Additionally, polymeric methyl and butyl methacrylates and higher homologues are applicable.

The techniques attendant the present invention may be utilized in conjunction with fibrous, porous and continuous surfaces. Articles to be treated are textiles of the woven and unwoven variety. In the treatment of fabrics, 0.05 to 5 percent (preferably O.l to 3 percent by weight of the fluorocarbon polymer on the weight of the fabric produces desirable surface properties. Illustrative textiles which can be advantageously treated with the fluorocarbon polymer are those based on natural fibers, e.g., cotton, wool, mohair, linen, jute, silk, ramia, sisal, kenaf, etc., and those based on synthetic fibers, e.g., rayon, acetate, acrylic, polyester, saran, azylon, nytril, nylon, spandex, vinyl, olefin, vinyon and glass fibers. (These designations of synthetic fibers are the generic terms set up by the Federal Trade Commission.) The treatment of these fabrics with the compositions of this invention imparts no adverse effect on the hand of the fabric and in some cases has a softening effect, thereby improving the hand.

The fluorocarbon polymer is applied by impregnation through exhaustion techniques. Excellent water and oil repellency and soil resistance are obtained on textile fabrics which are treated simultaneously with a fluorocarbon polymer and conventional finishes, such as mildew preventatives, moth resisting agents, crease-resistant resins, lubricants, softeners, sizes, flame retardants, antistatic agents, dye fixatives, and other water repellents.

The amount of the fluorocarbon polymer used in the exhaustion solution may be varied within wide limits, depending on the type of substrate employed and on the end use requirements for water repellency, oil repellency and durability. The following ranges are preferred, and give excellent results on many types of substrates such as fabrics:

a. 0.25 to 10 percent of an aqueous dispersion of the fluorocarbon polymer compound.

b. Nonionic surfactant may vary from 0. 1-10 percent.

c. Sufficient acid to produce pH of 3.0 to 5.5, with a preferred range of pH 4.5 to 5.5, to thereby insure at least approximately 70 percent exhaustion.

Several tests can be employed to establish the efiectiveness of the present process for imparting water repellent and oil repellent properties to the various substrates.

While a number of tests have been devised to determine the degree of stain resistance of fabrics and the subsequent launderability thereof, many of the tests fail by reason of the difficulty of making such tests consistently reproducible. Colgate-Palmolive research scientists have developed an ingenious test system which overcomes the shortcomings of the previous tests. Essentially, their method consists of placing onto the fabric measured volumes of standard common staining materials and comparing the size and intensity to a visual standard. In this way a semiquantitative estimation of the staining characteristics of a given fabric is obtained.

The test technique employs three water borne stains, namely, (l) chocolate milk, (2) black coffee and (3) imitation Coke"; and three oil borne stains, namely, (4) blue dyed corn oil, (5) French dressing and (6) blue dyed petroleum oil.

The staining materials mentioned in the above have the following compositions:

l. Chocolate Milk Stain cc. evaporated milk 20 cc. corn syrup 20 cc. chocolate syrup 60 cc. water This stain should be prepared once a week and kept refrigerated.

2. Black coffee 1.5 g. instant coffee 98.5 g. boiling water The coffee solution is allowed to cool until it reaches 70-80 F. The stain should not be kept for more than 8 hours.

when only the initial stain reaction is determined.

The following specific examples will further illustrate the practice of the invention but are not to be deemed to limit the scope of the invention to any procedural or other details there limitation Coke set forth. 50 cc. Coke syrup 50 cc. isopropanol EXAMPLES l and u 100 water I A base formulation is prepared consisting of 1.5 ml. per- Blue Dyed t cent solids emulsion of trihydro erfluoroheptyl acrylate 0.40 g. blue dye is added to 400 g. corn oil with stirring and lo polymer, of 3.0 ml. 10 percent so ids emulsion of poly-2,

heat in order to obtain a uniform solution. dichlorobutadiene extender and of ml. 1 percent solution 5. French Dressing of lgepal CO 630 (nonylphenoxyethylene-oxyethanol). The Once a bottle is opened, it should be stored in a refrigerator. mixture is mixed in 100 ml. of water. One-half portion of the 6. Blue Dyed Petroleum Oil resultant is acidified with 0.5 ml. 10 percent acetic acid solu- Two hundred fifty grams of oil are mixed with 0.1 percent 15 tion to give example I. The other portion is acidified with 2.0

blue dye by weight of the oil. The mixture is agitated and ml. 10 percent acetic acid solution to give example ll. warmed in order to obtain a uniform solution. The one portion is diluted with l,i00 ml. water to which 60 The test in the instant case is a static stain repellency test in grams f 80 80 cotton wa ches are added and agitated at that the fabric surface is given a minim m di t b reciprocations per minute Tergotometer. The other portion of In application the t m t f th t i materials i 2 the base is similarly diluted and used in treating another 60 between 70-80 F. A piece of white fabric approximately 7 grams of 00mm swalchesin he b 7 in h i l d on bl i paper on a h d uyu After drying the swatches are ironed at 400 F. The speed of f 1% f h test stain i f ll l d (not ironing relates to the function of repellency obtained as lS d o d) i separate areas on h f b i Af 2 minutes h evidenced in the table set forth below. The testing techniques excess t i i l, if any, i removid using a vacuum 2 are based on the Colgate-Palmolive test procedure set forth in tion line without coming in physical Contact with the stained the above w maximum ratings of 60 pes at the end of surface. The stained area is brushed twice lightly in opposite each test. -7 repellency and laundel'ablmynext P g directions with a straight motion of a dry absorbent tissue to for u Colgate-Palmolive Test p v i i. i i i i7 i .4i 0nd of Ironing Repellency Launderabillty exhansat 400 F. dfiHfiWfiA w tion (see/ft?) W.B 0.13. Total- W.B O.B Total Example:

44 4, 5 6 10. 5 14. 5 6 20. 5 I H 15. 6 as 4 6 10 14 (i 20 132 4 5. 5 S). 5 14 5. 5 19. 5 44 10. 5 13. 5 34 27. 5 7 34. 5 II 4. 7 88 1s. 5 14. 5 33 2o 13 42 132 1s 1s) 37 2s) 13. 5 42. 5

remove any unabsorbed stain material.

The stains are rated against the white background of a clean blotter. Ratings of I through 5 are arrived at strictly on size (relative spread) of an individual stain while rating 6 through 10 determines relative wetting as measured by intensity of the stain against a standard.

ln other words, a stain not even wetting the fabric could not change the color of the fabric and would have been completely removed from the surface thereof. The rating, therefore, would be 10. With increasing wetting of the area to which the stain has been applied there would be a greater color intensity therefore a lower rating until 6 is reached, whereupon, if the stain has migrated from its original boundary then one can as sume complete wetting of the original area so that degree of migration becomes the determining factor. The greater the migration, the lower the number given. It will be appreciated that the test system is based on relative values, and yet pro vides unique reproducible valid results.

The three water borne stains are added together to give a possible maximum of 30. These may then be totaled for a maximum of 60.

To arrive at the launderability portion of the test, the stained fabrics are dried 24 hours. Laundering is then carried out by washing in an automatic washer with a quantity of a conventional detergent. The fabrics are then dried in an automatic dryer at the appropriate setting for the fabric type. They are then lightly dry ironed (stain side down) at the appropriate fabric setting.

The rating of launderability of stains is based on the same l-lO system used for the static stain repellency tests. Again, it will be noted that the maximum rating after adding the results of the water borne stains will be 30, and similarly will be the total results regarding the oil borne stains. These two may be added together.

By rating both the initial static stain repellency and the launderability, a complete picture can be obtained not possible It will be noted that the example ll, having the lower pH. gives better results in repellency and launderability. Further, it will be appreciated that less ironing is required to achieve an acceptable level of repellency and launderability, clearly providing a more efficient curing.

We claim:

l. A method for developing a degree of increased oil and water repellency in connection with a fibrous substrate comprising immersing said substrate in an aqueous medium at a pH of between 3.0 to 5.5 and containing a fluorocarbon polymer emulsion capable of imparting oil and water repellency to said fibrous substrate and a quantity of a nonionic material capable of functioning as an exhaustion assistant for the fluorocarbon polymer, wherein said nonionic material is present in the range of from about 0.l to 10 percent by weight.

2. The method of claim 1 wherein the pH is between 4.5 to 5.5.

3. The method of claim 1 wherein the substrate is subjected to a heating step after application whereby the fluorocarbon polymer is cured to give increased oil and water repellency characteristics.

4. The method of claim I wherein the quantity of fluorocarbon polymer in the aqueous medium is in the range of 0.25 to 10 percent by weight.

5. The method of claim 1 wherein the nonionic material is a surfactant.

6. The method of claim 5 wherein the surfactant is nonylphenoxyethyleneoxyethanol.

7. The method of claim 6 wherein the fluorocarbon polymer is a trihydroperfluoroheptyl polymer.

8. The method of claim 7 wherein the acidification is achieved with acetic acid.

It 0 i it 

2. The method of claim 1 wherein the pH is between 4.5 to 5.5.
 3. The method of claim 1 wherein the substrate is subjected to a heating step after application whereby the fluorocarbon polymer is cured to give increased oil and water repellency characteristics.
 4. The method of claim 1 wherein the quantity of fluorocarbon polymer in the aqueous medium is In the range of 0.25 to 10 percent by weight.
 5. The method of claim 1 wherein the nonionic material is a surfactant.
 6. The method of claim 5 wherein the surfactant is nonylphenoxyethyleneoxyethanol.
 7. The method of claim 6 wherein the fluorocarbon polymer is a trihydroperfluoroheptyl polymer.
 8. The method of claim 7 wherein the acidification is achieved with acetic acid. 